REM behavior disorder, or REM sleep behavior disorder, involves unusual actions or behaviors during the rapid eye movement (REM) sleep phase.
REM behavior disorder, or RBD, is a type of parasomnia. Parasomnias are sleep disorders in which strange or dangerous events occur that affect or intrude on sleep. Other examples include sleep terrors, nocturnal dissociative disorder, sleepwalking, and sleep talking.
RBD is most likely in men over the age of 50 years. It is rare in women and children. Fewer than 1 percent of people have this condition.
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What is REM sleep behavior disorder?
People with RBD may try to act out their dreams while asleep.
REM sleep is a phase of the sleep cycle that normally occurs every 1.5 to 2 hours during an ordinary night's sleep.
During the REM phase of sleep, the body usually goes through a series of temporary muscle paralyses.
For people with RBD, these paralyses are incomplete, or they may be completely absent, so the person acts out their dreams, sometimes in dramatic or violent ways.
The lack of the temporary muscle paralysis causes sleepers with RBD to become physically agitated, actively moving their limbs, getting up, and engaging in actions associated with waking. A person may talk, shout, scream, hit, and punch during their sleep.
In some cases, the sleepers with RBD can injure themselves or whoever they share their bed with.
Physically violent movement is more likely if the person is having a violent or frightening dream.
If the person is awakened, they may remember their dream, but they may have no idea that they were moving.
Episodes of RBD may occur up to four times a night, one with each REM phase. More rarely, they may only occur once a week or even once a month.
The episodes tend to manifest towards the morning hours, when REM sleep is more frequent.
Causes of REM sleep behavior disorder
Exactly what causes RBD is unclear, but people who experience it may later develop more serious cognitive and neurological problems.
RBD has been linked to post-traumatic stress disorder and anxiety.
Neurologists have found that RBD is common among patients with degenerative neurological conditions, such as Parkinson's disease, multiple system atrophy, diffuse Lewy body dementia, and Shy-Drager syndrome. People with narcolepsy are also more likely to be affected by RBD.
RBD can be a precursor for certain neurodegenerative diseases. One study found that 38 percent of patients with RBD developed symptoms of Parkinson's disease about 12 to 13 years later.
RBD has been linked to apathy, lower scores in attention, cognitive issues, problems with executive functioning, and anxiety.
It may also be an adverse reaction to certain drugs, and it may occur during strict drug withdrawal. Heavy drinkers who suddenly withdraw from alcohol may experience RBD.
Studies suggest that antidepressants trigger RBD in up to 6 percent of users. Evidence has linked it with post-traumatic stress disorder (PTSD), and it can affect people who have recently experienced trauma.
RBD may occur alongside other disorders, such as daytime sleepiness, sleep apnea, periodic limb movement disorder, and narcolepsy.
How is REM sleep behavior disorder diagnosed?
Some other parasomnias may be confused with RBD. For an accurate diagnosis, the patient should be assessed at a recognized sleep center with staff with experience in dealing with parasomnias.
The patient may be kept under observation throughout the night. Their sleep, brain and muscle activity will be monitored, and any lack of muscle paralysis during REM sleep will be detected.
The assessment will also rule out other possible causes of parasomnias.
Treatment for REM sleep behavior disorder
REM behavior disorder can usually be treated successfully, through the use of medication and by adapting sleep habits.
Depending on the symptoms, a number of medications have proven effective in cases of RBD.
Low doses of clonazepam, from the benzodiazepine class of drugs, can help in about 90 percent of cases. These drugs suppress muscle activity and relax the body during sleep.
If the patient does not respond to clonazepam, some antidepressants or melatonin may help to reduce violent behavior.
Ways of improving sleep habits include adopting a predictable sleep-wake cycle to avoid sleep deprivation and avoiding alcohol consumption.
The following strategies can help to keep a patient and their sleeping partner safe:
Since RBD may be a precursor for neurodegenerative disorders, such as dementia and Parkinson's, it is a good idea to consult a neurologist if a person experiences symptoms.
As signs and symptoms of Parkinson's disease may not appear for over 10 years after the onset of RBD, the patient should have regular follow-up checks.
Prognosis for REM sleep behavior disorder
In time, the movements involved in RBD may become more violent, so it is important to seek medical advice.
If no cause can be identified, the symptoms can be controlled with drugs and there are usually no complications.
However, if there is an underlying neurological disease, the prognosis will depend on that disease.